Investigating Earth's Ancient Secrets

Paleoproterozoic Earth history and tectonic evolution

I am interested in the stratigraphy, geochemistry, and tectonic setting of sedimentary basins, particularly those formed prior to the Trans-Hudson orogeny around 1.8 billion years ago, in order to better understand the formative tectonic events of the Canadian Shield, as well as planet-altering episodes such as the Great Oxidation Event. My Discovery Grant northern research has focused on investigating the Paleoproterozoic Belcher Group and its role in preserving clues of the Trans-Hudson orogeny, especially within its youngest sedimentary units.

Recently investigated Paleoproterozoic sedimentary strata encompass the Belcher Group in Nunavut, the Pine Lake greenstone belt and Murmac Bay Group in northern Saskatchewan, and the Karrat Group in Greenland. Provenance analysis conducted by my team has contributed significantly to comprehending the assembly of cratons surrounding opposite ends of the Rae craton as well as the Superior craton. Ongoing work is investigating the provenance of smaller terranes within the Trans-Hudson orogen internides. My PhD work focused on the Penrhyn and Piling groups—two Paleoproterozoic sedimentary successions located in the arctic tundra of Nunavut, which provides me with a unique perspective for sedimentary strata investigations in West Greenland as they are traditionally thought to be correlative and represent similar syn-orogenic strata in the Trans-Hudson orogeny.

My research also investigates enigmatic tectonic events such as a proposed “tectonic shutdown event” that occurred almost simultaneously with the Great Oxidation Event. My PhD work investigated this “gap” in Earth's magmatic record and showed a mismatch between the zircon record of global river systems and the Paleoproterozoic magmatic record preserved in the igneous and sedimentary records of ancient cratons around the world, but especially the Canadian Shield.

The overlap in timing with the Great Oxidation Event led to another area of inquiry as to how atmospheric oxygenation might have affected solid Earth processes. We observed a step-change in a global compilation of zircon oxygen isotope composition over the Great Oxidation Event that we attributed to subduction of oxidized material from surface environments. Much of my previous research has investigated the impact of oxygenation on the surface environment in the atmosphere-ocean system but this study involved “deeper” thinking!

A more recent investigation reports the nature of one example of this early Paleoproterozoic magmatism, which is considered globally rare. We studied post-collisional A-type granitoids within the Arrowsmith orogeny via zircon U-Pb, Hf, O isotopes that were emplaced during the “tectono-magmatic lull” around 2.4 to 2.2 billion years ago. Notably, A-type granites are often overlooked in studies of ancient and poorly defined orogenic regions, but provide valuable insights into the distribution and duration of orogenic collapse.

Geochemical, paleoenvironmental and climatic reconstructions of Precambrian and modern Earth

The shift from an anoxic to a fully oxygenated Earth, where complex life could flourish, remains one of the most significant but poorly understood transitions in Earth's history. Multiple lines of evidence suggest this transition occurred during the early Paleoproterozoic. Despite decades of study, the precise timing and magnitude of the "Great Oxidation Event" (GOE) are still widely debated. Traditional models typically indicate a gradual increase in Earth's oxygen content around 2.4 billion years ago, continuing until complex animals emerged at the end of the Proterozoic.

I am interested in the link between global tectonic processes and biogeochemical cycles, including factors behind Precambrian atmospheric O₂ fluctuations. This takes the form of many different scales of observation and analysis, from the micro-scale to considering how continental collisions played a role.

My PhD research provided valuable insights into Earth's surface oxygenation dynamics by tracking uranium (U) concentrations in shale and iron formations, spanning a significant portion of the geological record. This research revealed that the rapid rise of atmospheric oxygen during the early Paleoproterozoic was followed by a marked decline towards less oxygenated conditions.

Building upon previous work on U concentrations in marine rocks throughout geological time, we investigated a more geologically-recent example of lower-O₂ oceanic conditions that occurred during Ocean Anoxic Event 2. We studied the U isotope systematics of samples that were deposited in the Western Interior Seaway (present-day Colorado). This study highlighted the role of local geochemical and depositional conditions in U cycling amid whole-ocean chemistry fluctuations, which has implications for Precambrian marine paleoredox reconstructions.

Origin and geological setting of critical and non-critical mineral deposits

My research involves collaborations with government geological surveys and industry partners to understand the geological background and origin of various types of both critical mineral and non-critical miniralcommodities including base metal, gold, and rare earth elements (REE). Partnering with Saskatchewan-based exploration companies and the Saskatchewan Research Council, we are studying the rare earth element (REE) mineralization along the margin of the Wollaston Domain of northern Saskatchewan supported by an NSERC Alliance Missions grant.

We are also studying the mineralogical and geochemical attributes of gold mineralization within the Pine Lake greenstone belt, Glennie Domain, in northern Saskatchewan in the vicinity of Saskatchewan s only producing gold mine. This work is focused on discerning the relationship between mineralization stages, alteration assemblages, and geological processes in the context of the Reindeer orogeny and subsequent Trans-Hudson orogeny. Ongoing investigations include stratigraphy and the sedimentary record of orogenesis in the Glennie Domain. This research is supported by NSERC in collaboration with SSR Mining, Inc.

In collaboration with the Geological Survey of Denmark and Greenland and Ministry of Mineral Resources (Greenland) on their Karrat Zinc Project, regional geological investigations centered on sediment-hosted Pb-Zn mineralization and the potential for other commodities in West Greenland. One of the outcomes of this research was understanding the processes, timing, and deposit models related to the Mârmorilik and Qaarsukassak formations, including the historic Black Angel mine.

Moving back in geological time, Archean greenstone belts of the Slave craton hold the secret to many geological processes that were unique to the Neoarchean and important for the final amalgamation of the Earth s earliest craton (nucleus to a continent). Recent investigations of volcanic and sedimentary rocks of the Beaulieu belt, Winter Lake greenstone belt, and Point Lake belt have focused on reconstructing their depositional and tectonic environments. All three belts to varying degrees contain prospective base metal mineralization in the form of volcanogenic massive sulfide (VMS) mineralization. For example, investigation in the Neoarchean Beaulieu belt resulted in the volcanic stratigraphy and tectonic context around the Sunrise VMS deposit. This research is supported by NSERC in collaboration with the Government of the Northwest Territories and the Northwest Territories Geological Survey.